An alpha-D-galactopyranosyl-containing glycoprotein was isolated from a membrane fraction of Ehrlich ascites tumor cells by affinity chromatography on a column of immobilized Bandeiraea simplicifolia lectin. The glycoprotein will be characterized with regard to its amino acid and carbohydrate composition. The carbohydrate moiety will be sequenced using the techniques of methylation analysis, Smith degradation and cleavage with purified glycosidases. Fluorescein-labelled lectin will be employed to assay for alpha-D-galactosyl containing micromolecules in a wide variety of prokaryotic and eukaryotic cells and tissues.